Cardiology

Value and limitations of 12-lead ECG monitoring

Paul Kligfield, M.D.
Professor of Medicine
Division of Cardiology, Department of Medicine
Weill Medical College of Cornell University
New York- Presbyterian Hospital
New York, New York 10021

Email: pkligfi@med.cornell.edu

The whole article available in PDF: 120 KB

During the past decade, increasing attention has been focused on the use of multi-lead monitoring for bedside monitoring, telemetry, and ambulatory electrocardiography. There are immediate advantages of 12-lead monitoring for the detection and localization of acute ischemia in patients with coronary artery disease. These methods are also valuable for the detection and accurate diagnosis of arrhythmia, because multi-lead recordings provide evidence of P wave and QRS complex morphology that cannot be determined from two- and three-channel recordings. Leads beyond the standard bipolar pairs are essential for the measurement of ECG findings that are derived from comparison of multiple unipolar leads. Other advantages may include increased reliability of basic QRS detection, since the redundancy of signal with multiple lead recording provides alternate sources of information when there is overwhelming noise in one or two single leads. And ultimately, 12-lead recording represents a potentially unified signal acquisition method that can be utilized for bedside monitoring, for ambulatory recording or telemetry, for exercise testing, and, with modification, also for standard electrocardiography.

With respect to ischemia, 12-lead monitoring provides increased sensitivity for the ST segment elevation patterns that occur with acute coronary syndromes such as myocardial infarction. In this setting, ST segment elevation provides important information regarding the localization of myocardial injury and the corresponding culprit coronary artery. The waxing and waning pattern of ST segment change in patients with dynamic ischemia is best observed in multiple leads. In myocardial infarction, the extent of injury can be estimated from the magnitude of ST segment elevation and its spatial distribution over the heart. After angioplasty, the 12-lead recording can provide a "fingerprint" for the pattern of ST segment change that can more reliably identify restenosis (reoccludion) of the involved coronary artery. Multiple leads also can enhance the sensitivity of the ECG for the ST segment pattern of subendocardial ischemia found during ambulatory recording and during exercise testing.

Last updated: 1 September 2001Created
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